This inductance bridge uses an external audio signal. The circuit is from a Radio Electronics from January 1966. The instrument can be a common multimeter in the lowest current range.
We found this ladder-shaped signal generator circuit in Radio Electronics magazine from August 1966....
This powerful regulator, shown in the figure is for 5V (TTL) is suggested by Motorola and makes use...
The L3 coil is what basically determines the resonant frequency, around 1 MHz, in this oscillator found...